Heretofore, a technique has been known in which a combined image as a view from a virtual viewpoint is generated using images captured by a plurality of cameras mounted on a vehicle (Japanese Patent Application Publication No. 2012-253428). In Japanese Patent Application Publication No. 2012-253428, the combined image is displayed on a display to notify the driver of the environment (e.g. following vehicle) around the host vehicle. However, in a case where the virtual viewpoint is set behind the host vehicle as in Japanese Patent Application Publication No. 2012-253428, the position of the virtual viewpoint moves with the driver's steering. Then, as the position of the virtual viewpoint moves, a following vehicle displayed in the combined image may possibly disappear, making it difficult for the driver to grasp the situation around the host vehicle.